Process of preparing pictures from light-sensitive layers containing organic colloids



Patented Aug. 13, 1929.

UNITED STATES PATENT OFFICE.

GUSTAV KGEL, OF KARLSRUHE, BADEN, GERMANY.

PROCESS OF PREPARING PICTURES FROM LIGHT-SENSITIVE LAYERS CONTAINING ORGANIC COLLOIDS.

No Drawing. Application filed August 11, 1928, Serial No. 299,127, and in Germany September 2, 1926.

I have filed an application on this invention in Germany, No. K. 100,598,, filed on September 2, 1926.

My present invention relates to a process of preparing pictures from light sensitive layers containing organic colloids.

A number of photographic processes based on the fact that on exposing organic colloids to light in the-presence of chromates their solubility and swelling property are modified, is already known.

All the colloid layers which have been rendered light-sensitive by means of a chromate, have the disadvantage that when they have been made quite ready for use they retain in this state their stability only for a short time. For this reason attempts have been made to modify the above mentioned processes by using instead of the chromates other light-sensitive metal salts.

In this connection reference may be made to the British patent specification No. 127,- 953 on June 5, 1918, (T. P. l\/Iiddleton) according to which the light-sensitiveness of silver salts is employed for said purpose, and to the German specification No. 160,729, of May 8, 1903 (Dr. Ludwig Strasser), according to which metal compounds in general areused, which by themselves do not undergo any reduction on their support without the action of light, but which .are reduced by the action of light. According to the processes described in these specifications, the exposure of these sensitive layers to light is followed by an after-treatment with chromates, in order to obtain a sufficient tanning or hardening effect. The pr0cesses in question have, however, not been adopted in practice.

My present invention is based on the discovery that by exposing to light layers of organic colloids containing light-sensitive organic bodies, such as quinones, and aftertreating these layers with a solution of a chromate or a solution of a similar acting body or bodies similar effects are produced to those obtained by exposing layerscontaining chromates to light. The layers obtainable according to my present invention have, however, the advantage of being of a greater durability than is the case with the known papers.

The new process may be used for all purposes appertaining to the arts to which it rela s. For ins ance it may be utilized in the manufacture of pigment-copies, copper prints by the intaglio printing method, rcflex copies, photo-lithographs, photographic prints, and the like, that is to say, the new method is applicable in all processes which are based on the light-sensitiveness of coll'oid-chromate layers by suitably adapting it to the respective purposes.

It is, of course, to be understood that, in the new process all the after-treating methods used in the preparation of chromatelayers may be applied, for instance, the materials may be subsequently dyed.

The following examples illustrate my invention; the parts being by weight:

1) A paper provided with a gelatine layer is immersed in a solution of 10 parts of sodium 2.7-anthraquinone disulfonate in 100 parts of water and then dried. The paper is then exposed to light under a so-called Raster negative, dipped 'into a 2% solution of potassium bichromate, whereupon it is washed with water and dried. The further treatment is carried out in the manner usual in the manufacture of photo-lithographic prints.

(2) An emulsion is prepared from 10 parts of gelatine, 2 parts of colcothar, one part of glycerine, 0.5 part of .stilbene phenylazonium chloride (cf. Bericht der Deutschen Chemischen Gesellschaft volume 24, page 1240 and volume 32, page 3128) and 100 parts of water and this solution is poured on paper. A pigment paper is thus obtained, which after being exposed to light under a streak positive andsoaked in a 2% solution of potassium bichromate, can be transferred on to copper in order to be subsequently developed and etched in the usual manner.

(3) 4 parts of the potassium salt of phenanthrenequinonesulfonic acid, obtainable by sulfonating phenanthrenequinonp, are dissolvedin 100 parts of water. Pigment paper is sensitized with this solution. After drying the paper is exposed to light under a negative and transferred on to a suitable base with a 2% solution of potassium bichroafter exposing the layer to light, aftertreating it with a chromate solution.

2. The'process of preparing pictures from light-sensitive layers containing organic colloids which consists in incorporating into the layer a-quinone as a light-sensitive organic body and after exposing the layer to light, after-treating it with a chromate solution.

3. The process of preparing pictures fromlight-sensitive layers contalning organic colloids which consists in incorporating into the layer a water-soluble quinone as a lightsensitive organic body and after exposing the layer to light, after-treating it with a chromate solution.

4:. The process of preparing pictures from light-sensitive layers containing organic collolds whichconsists in incorporating into the layer an anthraquinonesulfonic acid as a light-sensitive organic body and after exposing the layer to light, after-treating it with a chromate solution.

5. The process of preparing pictures from light-sensitive layers containing organic colloids which consists in incorporating into the layer sodium 2.7-anthraquinoncdisulfonate and after exposing the layer to light, after-treating it with a solution of potassium bichromate. 1

In testimony whereof, I afiix my signature.

GUSTAV KoGEL. 

